1B Foundations 2 - Teratogenesis

Question 1

What embryonic structure (derived from the hypoblast) serves as a secondary energy source?

Answer 1

Endodermal yolk sac

Question 2

What embryonic structure serves as a reservoir of nonspecialized (undifferentiated) stem cells?

Answer 2

Endodermal yolk sac

Question 3

What are the three germ layers that derive from the epiblast?

Answer 3

Ectoderm
Mesoderm
Endoderm

Question 4

Fetal development weeks 3-8. Embryonic period.

Answer 4

Organogenesis
Neural tube formed by neuroectoderm and closes by week four
Extremely susceptible to teratogens

Question 5

Fetal development within week 1

Answer 5

hCG secretion begins after implantation of blastocyst

Question 6

Fetal development within week 2

Answer 6

Bilaminar disc (epiblast, hypoblast)
2 weeks = 2 layers

Question 7

Fetal development week 4

Answer 7

Heart begins to beat. 4 chambers.
Upper and lower limb buds begin to form
4 week = 4 limbs

Question 8

Fetal development within week 3

Answer 8

Trilaminar disc
3 weeks = 3 layers
Gastrulation
Primitive streak, notochord, mesoderm and its organisation, and neural plate begin to form

Question 9

Fetal development day 0

Answer 9

Fertilization by sperm forming zygote, initiating embryogenesis

Question 10

Fetal development week 8 (Start of fetal period (movement begins))

Answer 10

Fetal movement, fetus looks like a baby

Eight rhymes with gait

Question 11

Fetal development week 10

Answer 11

Genitalia have male/female characteristics.

TEN rhymes with PENis

Question 12

ACE inhibitors causes which teratogenic malformations?

Answer 12

Renal

Question 13

Aminoglycosides causes which teratogenic malformations?

Answer 13

CN VIII toxicity (Ototoxicity)

“A MEAN GUY hit the baby in the ear”

Question 14

Fluoroquinolones causes which teratogenic malformations?

Answer 14

Cartilage damage (Animal studies)

Question 15

Tetracylines causes which teratogenic malformations?

Answer 15

Discolored teeth

Question 16

Cyclophosphamide causes which teratogenic malformations?

Answer 16

Ear/facial anomalies, limb hypoplasia, absence of digits

Question 17

Methotrexate causes which teratogenic malformations?

Answer 17

Neural tube defects (interferes with folate metabolism), abortion (abortifacient)
Category X drug

Question 18

Carbamazepine causes which teratogenic malformations?

Answer 18

Fetal hydantoin syndrome. Neural tube defects, craniofacial defects, fingernail hypoplasia, developmental delay, IUGR (Intrauterine Growth Restriction)

Question 19

Valproic acid causes which teratogenic malformations?

Answer 19

Inhibition of maternal folate absorption –> neural tube defects

Question 20

Phenytoin causes which teratogenic malformations?

Answer 20

Fetal hydantoin syndrome: microcephaly, dysmorphic craniofacial features, hypoplastic nails and distal phalanges, cardiac defects, IUGR, mental retardation

Question 21

Lithium causes which teratogenic malformations?

Answer 21

Ebstein’s anomaly (atrialized right ventricle)

Question 22

Statins causes which teratogenic malformations?

Answer 22

CNS and limb abnormalities
(Interferes with cholesterol metabolism)
Category X drug

Question 23

Warfarin causes which teratogenic malformations?

Answer 23

Facial/limb/CNS anomalies, spontaneous abortion, bone deformities, fetal hemorrhage, opthalmological abnormalities.

“Not WARFARe on baby. HEPpy baby”
Category X drug

Question 24

Isotretinoin causes which teratogenic malformations?

Answer 24

Spontaneous abortions

Category X drug

Question 25

Diethylstilbestrol (DES) causes which teratogenic malformations?

Answer 25

Vaginal clear cell adenocarcinoma, congenital Mullerian anomalies Category X drug

Question 26

Thalidomide causes which teratogenic malformations?

Answer 26

``` Limb defects (Phocomelia)("flipper" limbs) Category X drug ```

Question 27

Non-medicinal-drug causes whith teratogenic potential?

Answer 27

``` Ionizing radiation Excessive vitamin A Maternal diabetes Iodine deficiency Cocaine, tobacco ```

Question 28

Fetal Alcohol Syndrome features

Answer 28

``` Smooth philtrum Thin upper lip Small palpebral fissures Wide set eyes (Also cleft lip/palate) ``` Developmental delay Intellectual disability Nr one cause for intellectual disability in USA Microcephaly Holoprosencephaly

Question 29

Synpolydactyly Definition?

Answer 29

Extra fused digits (i.e. between 3rd and 4th fingers)

Question 30

Homeobox (HOX) Genes. What do they do?

Answer 30

Blueprint for skeletal morphology | Code for transcription regulators

Question 31

Mutation in HOXD-13?

Answer 31

Synpolydactyly (between 3rd and 4th fingers)

Question 32

What can alter HOX gene expression?

Answer 32

Retinoic acid

Question 33

HOX mutations (in general)

Answer 33

Appendages in wrong locations

Question 34

Where are Sonic hedgehog genes produced?

Answer 34

Base of limbs in zone of polarizing activity

Question 35

What are Sonic hedgehog genes involved in?

Answer 35

Patterning along anterior-posterior axis. | Involved in CNS development.

Question 36

Mutation in Sonic hedgehog genes causes?

Answer 36

Holoprosencephaly

Question 37

Where is the Wnt-7 gene produced?

Answer 37

Apical ectoderm ridge

Question 38

What is the Wnt-7 gene involved in?

Answer 38

Necessary for proper organization along dorsal-ventral axis. (So that feet and nose point in the same direction)

Question 39

Where is the FGF gene produced?

Answer 39

Apical ectodermal ridge

Question 40

What is the FGF gene involved in?

Answer 40

Stimulates mitosis of underlying mesoderm, providing for lengthening of limbs.

Question 41

Mutation in FGF gene causes?

Answer 41

Short limbs

Question 42

Which antibiotics are potentially teratogenic?

Answer 42

Aminoglycosides Tetracyclines Fluoroquinolones

Question 43

Pregnancy category X drugs?

Answer 43

``` Methotraxate Statins Warfarin Isotretinoin Diethylstilbestrol Thalidomide ```

Question 44

Most common cause of neural tube defects?

Answer 44

Folate deficiency Also: Most common vitamin deficiency in the US

Question 45

Most common cause of congenital malformations in the US?

Answer 45

Alcohol use in pregnancy

Question 46

Most common cause of congenital intellectual disability in theUS?

Answer 46

Fetal alcohol syndrome